Ken,
There are so many of these DTC labs. I don't now how we can check on them other than looking for a history and reviews. Someone in our local support group recommended Health Tests Direct...she has been happy with them, in business since 2001, and they were cheaper than DL on some test I checked. They still use both Quest and LabCorp, and give the patient the option. NMR did not come up searching Quest, but did when Switched to LabCorp:
https://www.health-tests-direct.com/ordering-page
Good luck!